<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        //javascript 由三部分组成：浏览器对象模型，文档对象模型，ECMA
        console.log(window);//BOM Borwer Object Model 浏览器对象模型
        console.log(document);//DOM Docunment Object Model 文档对象模型
    </script>
</body>
</html>